Loading device for concrete mixers



Dec. 2, 1930. ELL 1,783,532

LOADING DEVICE FOR CONCRETE MIXERS Filed March 16, 1927 Patented Dec. 2, 1930 UNITED STATES PATENT OFFICE JAMES E. BUSHNELL, OF NORTH PLAINFIELD, NEW JERSEY, ASSIGNOR TO RANSOME CONCRETE MACHINERY COMPANY, OF PLAINFIELD, NEW JERSEY, A CORPORATION or NEW was v LOADING DEVICE FOR CONCRETE MIXERS Application filed March 16, 1927. Serial No. 175,653.

The improvements relate primarily to loading devices for concrete mixers, in which the materialsusually cement, sand and gravel or crushed stoneare received, elevated and dumped into the mixer by a pivoted skip or charging hopper, but they may be employed for other purposes and with other substances.

In devices of this character a receptacle is employed to servethe combined purposes'of a receiving and'elevating bucket, and a charging hopper, arranged to be lowered to the ground to receive the materials and elevated to bring them to the level of the mixer to be charged and cause them to be discharged into the mixer by gravity. It has been found necessary in many cases to use shovel-s or other tools to cause a full discharge of the loader by gravity, or to hammer on it when it is in elevated, discharging position so as to cause a vibration and insure the gravita-' tion of its contents. Such practices, however, consume time and labor, and the practice of hammering or shaking the loader also results in considerable Wear and tear on the parts. The objects of the present improvements, among others, are to overcome the difficulty due to the tendency of the materials to stick in the hopper, without extra labor and without injury to undue wear or strain on the parts; Another object is to provide means from cushioning the shock of the pivoting means of the hopper.

The improvements are illustrated in the accompanying drawings, referred to herein, and in which Fig. 1 is a side elevation of a loading apparatus embodying the improvements, with fragments of the concrete mixer and its frame and truck indicated therein, to show the positions and relations'of the parts;

Fig. 2 is a rear view of the reinforced plate forming the pivoted hanging member supporting the lower pivot of the device;

Fig. 3 is an enlarged detail in elevation showing one of the jaws of the device with vibrating spring cushion.

The loading skip or hopper consists essentially of the receiving or bucket portion 1 adapted to rest on the ground in rece ving position, and the spout or hopper portion 2 through which its contents are discharged into the mixer. It is pivoted on the pivot bar 3 extending across the lower part of the upright plate 4, by means of rigid arms 5 and 6 secured to the upper or inner part of the hopper and connected with a plate 7 through bears the jaw members 11, 11 in which the channel 12 is mounted to reciprocate and to receive and engage the upper pivot bar 13. This member 12 is normally held in its outer position by the compression spring 14 between it and the bar 6, backing against the plate 14, and must therefore compress the said spring when it moves inwardly and be pressed outwardly thereby.

It will be understood that parts 5 to 14 inclusive are preferably duplicated on each side of the device, excepting bar 13. The pivot 13 is in the form of a bar or rod running through the turned sides of'the plate member 4 and the two right-angled uprights 5 of the main mixer frame, and the pivot 3 is a similar but shorter rod extending through and slightly beyond the sides of the .member 4 in like manner and through the that while rod 13 is permanently fixed on A uprights 5', rod 3 is carried wholly by parts 4, 5, 6 and 7 and being shorter than rod 13 passes between the forward limits of uprights 5 to contact with the rear or angled portions thereof, which serve to stop or limit the movement of elements 3 to 14, excluding 13, in their clockwise movement about pivot 13. The member 4 is preferably in the form of a plate of heavy sheet metal with its vertical side edges turned inwardly, but it may be made in other form, such as two side members connected by cross pieces, if desired.

Thefunctioning of this pivoted construction is obvious upon inspection of the drawings, it being the same as that set forth in the application of John P. Faber, filed June 2nd, 1925, Serial No. 34,281.

The pivoted charging device is'provided with a cable 15 attached to its outer end, by which it is raised and lowered, and this cable runs over sheaves 16 at the top of the frame to a suitable winding and unwinding mechanism. The mixing drum 17 may be mounted and operated in any desired manner, and is provided with a central charging opening 18.

In operation the pivoted charging device, after receiving while in lower position a load of materials, with which the mixer is to be charged, is elevated by means of the cable 15, turning in this first movement on the pivot bar 3, and until the sliding jaw member 12 engages the pivot bar 13. This brings it approximately to the position indicated by the lower dotted lines in Fig. 1, and from that position to the position indicated by the upper dotted lines in said figure it pivots on the rod 13 and the sliding jaw 12. During the latter part of the first operation, and the entire second operation, the contents of the skip are being discharged by gravity into the mixer, and by the time the upper position is reached, the said contents should be discharged and the mixing of them in the mixer commenced. It is important that the charging of the materials into the mixer shall be complete and thorough, and finished at the moment to which the charging operation is timed. If this does not occur, the materials will not all be mixed for the predetermined period of time necessary to meet the requirements, and other disadvantages will result. If, however, the materials are moist, or of such a character that they do not gravitate quickly and freely they will not be discharged in time, and may not be discharged at all, unless some means for manually causing them to flow from the hopper is employed. This, as before noted, is undesirable for various reasons. Another objectionable feature in devices of this character is that when the upper pivot jaw strikes the upper pivot, and checks the loaded skip in its movement in changing the direction of the said movement, the hoisting apparatus and other parts of the mechanism are subjected to severe strain, which will cause them to deteriorate and sometimes to break. Nevertheless, the double pivot is desirable, and has been found very useful, because it not only saves power, but enables the operator to give the skip a steeper inclination at the discharging point. This, it will be seen, is brought about by the movement of the skip first on the pivot 3 until its discharge end is at or little above horizontal and its receiving end well above horizontal, and rotation on the pivot 13 much closer to its body, the plate hanger 4 in this operation simply swinging outwardly on the pivot 13 and the pivot 3 with it.

The present improvements, therefore, absorb the shock at the time when the skip changes pivots. They also perform another and highly important function, because the shock of the sliding jaw 12 striking the pivot bar 13 causes the spring 14 to be compressed, and to expand and force the skip away from the pivot slightly as soon as the force of the impact is spent. This sets 'up a jumping or vibrating motion, which continues through the upper part of the movement of the skip and causes the materials therein to jump and gravitate freely, and while the principal vibrating movement of the skip or hopper is longitudinal a certain degree of lateral movement takes place due to oscillation and to the fact that the jaw 12 is large enough to permit some movement thereof on the pivot.

The construction and arrangement of the spring bearing for the upper pivot is such that the vibration of the skip is approximately longitudinal, so that its action is similar to that of a shovel when it is swung in the direction in which the shovelful of material is to be discharged, and suddenly stopped, so that the materials will leave the shovel on account of their momentum and travel in that direction. This action in the skip is due to the fact that the sliding channel members 12 which act as a bearing for the skip on the upper pivot slide longitudinally of the hopper section against the spring and in the opposite direction under the pressure of the spring, so that the vibrating movements of the skip are mainly lengthwise and tend to cause a sliding movement of the materials therein over its inner surfaces. The improvements therefore not only provide means for doing awa with other mechanism or manipulation or the purpose of causing a quick and clean discharge of the skip, but do this work more effectively because they act in the line of discharge and not angularly thereto.

The vibratory movement of the hopper is caused by one or more of the following agencies, viz: the impact of the sliding pivot engaging member on the pivot, causing compression of the spring and longitudinal movement of the hopper relative to the pivot, the rebound from said impact due to expansion of the spring, the pull of the hoisting cables on the hopper acting against the pivot and the movement of the materials in the hopper sliding and tumbling toward the discharge end of the hopper as the device is elevated. If the materials are of a very sticky character or for any reason do not gravitate automatically therefrom, hand operated or other means may be employed for causing or accelerating the vibration of the hopper on its upper pivot.

I claim:

1. In a device of the character described, an elevating and charging hopper arranged to be lowered to receive materials and elevated to discharge the same, means for low- I" ering and elevating the same, a pivot upon which the same moves in lower position and a second pivot upon which it moves in upper position, connecting members between said hopper and one of said pivots, one of said members being constructed and arranged to engage the second pivot when the hopper iselevated, and a yielding member between the hopper and the upper pivot, said last named member being yieldable substantially along the discharging axis of said hopper and adapted to cushion the impact of the pivot engaging member on the pivot and to permit longitudinal movement of the hopper, while the said pivot is engaged, relative to said pivot.

2. In a device of the character described, the combination with an elevating and discharging hopper, of a fixed pivot, a frame depending therefrom, a second frame pivoted to said first frame beneath said fixed pivot, said second frame being associated with said hopper for supporting same in arcuate travel about said pivots, and hopper vibrating means on one of said frames associated and cooperating with said fixed pivot and hopper when the latter approaches discharging position for reciprocating said hopper'with respect to said fixed pivot.

3. The combination with a mixing drum and a frame for supporting the same, of a loading hopper for the mixing drum, means for pivoting said hopper with reference to the frame consisting of a pendently hinged link, said link having a hinged connection at its free end with the loading hopper, means for swinging said hopper to drum-charging position and oscillatable means cooperating with said hopper and pivoting means when the former is in drum-charging position, said means being responsive to thrust movements of said hopper during its travel to drum-charging position whereby said hopper is vibrated with respect to said drum.

4. The combination with a frame and a charging hopper having upper and lower pivots for swinging said hopper about plural axes, of a member movable with said hopper for engaging said upper pivot, and a resilient element for said upper pivot and the hopper, said element being positioned for cooperating with said member substantially along the discharging axis of said hopper.

Witness my hand this 12th day of March, 1927, county of Union, State of New Jersey.

JAMES E. BUSHNELL. 

